1. Field of Invention
This invention is concerned with apparatus for heating water and more particularly concerned with hot water tanks having multiple stages for heating water by means of combustible fuel.
2. Description of Prior Art
Apparatus for pre-warming incoming cold water prior to feeding it to a hot water tank heated by combustible fuel is well known. The pre-warming or pre-heating of the incoming cold water takes place in a separate tank, usually in the same location, as the hot water tank. The pre-warming is obtained from the ambient temperature air surrounding the separate tank. After aborbing some of the ambient temperature air, the water is passed on to the hot water tank employing usually an oil or gas burner to complete the heating of the water to a desired temperature.